Impact of the COVID-19 pandemic on opioid toxicity mortality rates in Nova Scotia: An interrupted time series analysis (2009-2023).

Opioid toxicity refers to the clinical syndrome resulting from excessive opioid exposure, presenting as central nervous system depression, decreased level of consciousness, respiratory depression, cyanosis, and/or miosis. The most life-threatening feature of opioid toxicity is opioid-induced respiratory depression (OIRD), which is defined as a reduction in the drive to breathe due to opioid action at μ-opioid receptors in the brainstem respiratory centers, leading to hypoventilation, hypercapnia, and potentially apnea and death.– International opioid use has doubled in prevalence from 26–36 million people in 2010 to 61 million people in 2020 with epidemics currently ongoing in the United States, Canada, North Africa, West Africa, and the Middle East and Southwest Asia. According to the World Health Organization (WHO), of the 600,000 drug-related deaths in 2019, approximately 480,000 were related to opioids. In response, a range of harm-reduction strategies have been implemented including supervised consumption sites with immediate access to naloxone, where trained staff can identify and manage OIRD on site, reducing fatalities and hospital utilization.– Certain factors are associated with an increased risk of opioid toxicity: using opioids while alone; being male; < 25 years of age; being of Indigenous ancestry; having had previous episodes of opioid-induced respiratory depression, not being on any opioid agonist therapy; and having low socioeconomic status. Structural and access-related factors have also been associated with increased risk, including inconsistent drug supply with variable potency, limited availability of supervised consumption services, barriers related to policing practices, housing instability, limited access to regular healthcare, and food insecurity.– Standardized tools including the Glasgow Coma Scale (GCS), Richmond Agitation-Sedation Scale (RASS), and Pasero Opioid-induced Sedation Scale (POSS) may be used to assess sedation or mental status, but they do not reliably reflect the physiological changes of opioid-induced respiratory depression. The decision to administer naloxone versus providing only ventilatory support in opioid toxicity is guided by the presence and severity of OIRD, with initial management prioritizing support of the airway and breathing. Naloxone is not administered if the patient is breathing adequately, regardless of mental status.– For the layperson, especially in a stressful situation, it can be difficult to accurately assess respiratory rate, depth of breathing, and signs of hypoxemia or hypercapnia.